Serena Williams Rolls Into U.S. Open Semifinals. Now It Gets Interesting.

Ben Solomon for The New York Times

Sunsets have had more suspense than Serena Williams’s 6-1, 6-0 victory over Wang Qiang in the quarterfinals of the United States Open.

But no matter how impervious-to-pressure Williams looked under the lights on Tuesday night, the tension at this U.S. Open did not really start until now.

Since Williams’s return to the tour in 2018 after the birth of her daughter, Olympia, her problem at the Grand Slam tournaments has not been about finding form. It has been about sealing the deal.

She has often hit the high notes in early rounds and then run into a mental block, an opponent on a roll or a combination of the two when she was on the verge of winning her 24th…